update ifdef for _rotr on aarch64

Enables compilation on aarch64 (Packet c1.large.arm)

src/softAes.cpp

@@ -328,7 +328,7 @@ static inline uint32_t subw(uint32_t w) {
 		sbox[w & 0xff];
 }
 
-#if defined(__clang__) || defined(__arm__)
+#if defined(__clang__) || defined(__arm__) || defined(__aarch64__)
 static inline uint32_t _rotr(uint32_t value, uint32_t amount) {
 	return (value >> amount) | (value << (-amount & 31));
 }
@@ -374,4 +374,4 @@ __m128i soft_aesdec(__m128i in, __m128i key) {
 	);
 
 	return _mm_xor_si128(out, key);
-}
+}